Patent Document 1 exists as an art relating to the joint unit having the above-described construction. Patent Document 2 exists as an art relating to the pressed contact.
With the construction disclosed in Patent Document 1, a spherical head section 21 formed at a base 16 of a ball joint is housed in a housing 17 against inadvertent withdrawal therefrom. A neck portion 22 formed integral with the spherical head section 21 is caused to project to the outside of the housing 17. Further, a pressure from a threaded bar 19 provided in a retaining portion 11 is transmitted via an attachment 18 provided inside the housing 17 to the spherical head section 21, whereby this spherical head section 21 is brought into pressed contact against the inner surface of the housing 17. As a result, the pivotal angle of the base 16 relative to the housing 17 can be locked as desired.
The construction disclosed in Patent Document 2 includes: three gripping portions 11A, 11B, 11C which come into contact with a cylindrical outer peripheral surface 101 of an object to be gripped (“gripped object” hereinafter) 100 to be deformed toward the center of the gripped object 100, thus gripping this object 100; a first member 21, plate-like second members 22A, 22B pivotally jointed to the opposed ends of the first member 21; cylindrical members 23A, 23B provided at the ends of the second members 22A, 22B; a ball 26 disposed between the cylindrical member 23A and the gripping portion 11A: and a male screw member 43 configured to cause a pressure generated by an operation of a hexagonal wrench 40 to be applied to the first member 21.
According to this Patent Document 2, the second member 22A and the second member 22B are housed under flexed conditions thereof within a flexed-member accommodating hole 33. In response to a rotational operation of the male screw member 43, the pressure from the male screw member 43 is applied to the first member 21. Then, the force from this first member 21 displaces the second member 22A and the cylindrical member 23, as a result of which the three gripping portions 11A, 11B, 11C are brought into pressed contact with the gripped object 100 for gripping this object 100.